The focus of this project is to develop an in-situ manometer for continuous monitoring of Sphincter of Oddi (SO) pressure over a prolonged period of time as a means to accurately diagnose Sphincter of Oddi Dysfunction (SOD), as well as to advance the understanding of Sphincter of Oddi spasm to enable future treatment of this condition. The proposed manometer consists of a biliary stent with an open channel to permit uninterrupted flow of bile from the liver to the duodenum. An array of wireless, passive magnetoelastic pressure sensors are embedded along the length of the stent for real-time assessment of the pressure within the SO without the use of wires or specific sensor alignment. In the application described here, the responses of the sensors are conveyed to a device with data logger system to permit patients to electronically log symptoms such as abdominal cramps or pain. This feature permits establishment of a correlation, or lack of correlation, between pain attacks and sphincter spasm, which provides critical information for the diagnosis and treatment of SOD. Moreover, because pain attacks may occur infrequently, the monitoring stent can be left in situ until a typical pain attack occurs, after which the manometer can be removed. This project focuses on the development of the manometer. Although this project does not include a clinical trial to investigate the underlying causes of SOD, the development of the manometer alone would present an advance in medical diagnostic devices by providing a useful tool for further studies of SOD. Specific focuses of this project include {1} the fabrication and characterization of the magnetoelastic pressure sensors, {2} integration of the sensors into the stent, {3} fabrication of the measurement device, {4} calibration of sensor data, and {5} evaluation and optimization of the sensor system.Narrative [unreadable] Public Health Relevance: To date, there is no reliable way for long-term (from a few weeks to a few months) monitoring of the pressure within the Sphincter of Oddi (SO). The diagnosis of Sphincter of Oddi Dysfunction (SOD) is made on the basis of several minutes of SO manometry performed during Endoscopic Retrograde Cholangio- pancreatography (ERCP), during which the patient is fasting and sedated. Little is known about SO function in awake, ambulatory, non-fasting patients. This project, upon successful completion, will provide a tool for improved study of SO physiology and diagnosis of SOD since it can provide ambulatory, continuous monitoring of the pressure within the SO, and will allow correlation between SO pressures, activities such as eating, and episodes of pain. The ultimate goal of this project is to develop a passive, wireless implantable biosensor technology to improve diagnosis capabilities on various diseases. As an example, with proper modifications the same sensor technology can be applied for measuring the pressure within an artery stent for in-stent stenosis detection. [unreadable] [unreadable] [unreadable]